The present invention relates generally to refrigerator cabinets and in particular relates to a mullion assembly having an enhanced energy saving construction.
In the construction of a refrigerator cabinet, it is typical to include a metal mullion bar position between side walls of a horizontally disposed freezer and fresh food compartment or between the top and bottom walls of side-by-side freezer and fresh food compartment. The purpose of the mullion bar or rail is well known to provide support between the side walls of the refrigerator and to provide a load bearing structure about which the liners of the freezer and fresh food compartment are constructed.
The mullion rails or bars are located across the open front of the refrigerator cabinet exposed to the ambient atmosphere and at least a portion of the interior liner of the freezer compartment and/or the fresh food compartment. Typically, the mullion bar provides a structural support to which a partition for the freezer and fresh food compartments are constructed. Since the mullion bar is a metallic material, the mullion is a good heat transfer medium between the ambient atmosphere and the freezer compartment and/or the fresh food compartment. When the ambient is humid, condensation appears on the face of the mullion bar when mullion temperature is below dew point temperature. To prevent sweating the mullion bar typically has a heater which warms the mullion surface exposed to the ambient. However these heaters also heat the fresh food compartment and/or freezer compartment raising the energy requirements needed to maintain operation of the refrigerator.
The mullion bar also provides a reinforced surface against which the doors may close. Each door includes a gasket having magnets which are attracted to the metal mullion bar to effect a seal against the mullion bar. Thus the mullion bar is required to provide an effective seal against the door gaskets which must withstand the stresses of repeated door closure and provide a magnetic attracting medium.
There is a need however for a mullion bar assembly for use in a refrigerator where the metallic bar exposed to the ambient contacts only a portion of the door seal and another portion of the door seal further engages a portion of the interior cabinet or gasket associated therewith that is insulated from the metallic mullion bar. There is a further need to provide a mullion bar assembly that has improved thermal insulation characteristics that inhibit thermal transfer between the fresh food or freezer compartments and the ambient exposed mullion bar.
The present invention relates to a refrigerator cabinet having improved heat transfer characteristics associated with the mullion. Preferably, a metallic reinforcing mullion rail or bar is located between the freezer compartment and fresh food compartment of an interior plastic liner. The metallic mullion bar is held in place by plastic insulated edge wall gasket members which together with the mullion bar form the front wall of the mullion assembly. The edge wall gasket members have an additional function of holding a block of insulation behind the mullion strap to further reduce thermal heat transfer to the mullion bar.
In accordance with one aspect of the present invention there is provided a refrigerator including a refrigerator cabinet comprises an exterior metallic cabinet shell having a top wall, a bottom wall and side walls providing an open side. The cabinet has an interior liner adapted to fit within the exterior cabinet shell. The interior liner defines two interior cavities with a space therebetween. The cabinet has an energy efficient mullion assembly interconnecting the two interior cavities at the open side. The mullion assembly comprises the interior cavities each having adjacent edge wall members extending toward the open side of the cabinet. The edge wall members each have a forward surface extending flush to the open side for supporting a portion of a door sealing gasket. The edge wall members each has a recessed channel extending rearwardly of the open side. At least one of the edge wall members has a locating flange member with an edge portion extending toward the other one of the edge wall members. A metallic mullion bar extends between the pair of edge wall members and has a flat wall portion against which seals another portion of the door sealing gasket carrying a magnet. The mullion bar has rearwardly extending flanges extending into and supported by a respective one of the recessed channels of the edge wall members. The mullion assembly further includes an insulation member mounted rearwardly of the metallic mullion bar within the space between the interior cavities. The insulation member is held in engagement by and between the pair of edge wall members by the at least one locating flange member edge portion urging the insulation member against the other edge wall member.
By locating the insulation member between and by the insulating gaskets, thermal transfer is reduced from the interior cavities of the cabinet to the metallic mullion bar. Further, by supporting the mullion bar separate of the interior cavities, there is a reduction of heat transfer.
Preferably, the mullion assembly further includes a layer of mastic material positioned between the metal mullion flat wall portion and the insulation member and refrigerant tubing extending within the mastic material and into the insulation member for distributing and maintaining temperature of the metallic mullion flat wall portion above the dew point.
Preferably, the edge wall members are separate gaskets attached to a wall of the interior cavities. Preferably, the recess channels extend rearwardly at 90 degrees from the front forward surface. The recess channels are preferably defined by an outer wall adjacent the respective interior cabinet and an inner wall adjacent the insulation member and wherein one of the inner walls includes the locating flange member edge portion.
The insulation member preferably comprises a block of fiberglass insulation and foamed-in-place insulation is further provided within the space between the two interior cavities and rearwardly of the insulation member.